Documentation

Mathlib.Algebra.CharP.Invertible

Invertibility of elements given a characteristic #

This file includes some instances of Invertible for specific numbers in characteristic zero. Some more cases are given as a def, to be included only when needed. To construct instances for concrete numbers, invertibleOfNonzero is a useful definition.

theorem CharP.intCast_mul_natCast_gcdA_eq_gcd {R : Type u_1} [Ring R] {p : } [CharP R p] (n : ) :
n * (n.gcdA p) = (n.gcd p)
theorem CharP.natCast_gcdA_mul_intCast_eq_gcd {R : Type u_1} [Ring R] {p : } [CharP R p] (n : ) :
(n.gcdA p) * n = (n.gcd p)
def invertibleOfCoprime {R : Type u_1} [Ring R] {p : } [CharP R p] {n : } (h : n.Coprime p) :

In a ring of characteristic p, (n : R) is invertible when n is coprime with p, with inverse n.gcdA p.

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    Instances For
      theorem invOf_eq_of_coprime {R : Type u_1} [Ring R] {p : } [CharP R p] {n : } [Invertible n] (h : n.Coprime p) :
      n = (n.gcdA p)
      theorem CharP.isUnit_natCast_iff {R : Type u_1} [Ring R] {p : } [CharP R p] {n : } (hp : Nat.Prime p) :
      IsUnit n ¬p n
      theorem CharP.isUnit_ofNat_iff {R : Type u_1} [Ring R] {p : } [CharP R p] {n : } [n.AtLeastTwo] (hp : Nat.Prime p) :
      theorem CharP.isUnit_intCast_iff {R : Type u_1} [Ring R] {p : } [CharP R p] {z : } (hp : Nat.Prime p) :
      IsUnit z ¬p z
      def invertibleOfRingCharNotDvd {K : Type u_2} [Field K] {t : } (not_dvd : ¬ringChar K t) :

      A natural number t is invertible in a field K if the characteristic of K does not divide t.

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          def invertibleOfCharPNotDvd {K : Type u_2} [Field K] {p : } [CharP K p] {t : } (not_dvd : ¬p t) :

          A natural number t is invertible in a field K of characteristic p if p does not divide t.

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            Instances For
              instance invertibleOfPos {K : Type u_2} [Field K] [CharZero K] (n : ) [NeZero n] :
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                instance invertibleSucc {K : Type u_2} [DivisionRing K] [CharZero K] (n : ) :
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                  A few Invertible n instances for small numerals n. Feel free to add your own number when you need its inverse.

                  instance invertibleTwo {K : Type u_2} [DivisionRing K] [CharZero K] :
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                    instance invertibleThree {K : Type u_2} [DivisionRing K] [CharZero K] :
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